NiFe-bimetal-organic framework grafting oxygen-vacancy-rich BiVO₄ photoanode for highly efficient solar-driven water...

Bismuth vanadate (BVO) possesses great potential in photoelectrochemical water splitting application, but still suffers from low charge transfer efficiency as well as poor chemical stability. Herein, we have fabricated a thin NiFe-bimetal-organic framework (NiFe-MOF) layer grafting surface oxygen vacancies enriched BVO photoanode (NiFe-O_vac-BVO), which improves the charge separation and transfer efficiency during oxygen evolution process. Meanwhile, the NiFe-MOFs thin layer can not only protect the surface O_vac of BVO, but also efficiently inhibits the photocorrosion. As a result, the resultant NiFe-O_vac-BVO exhibits good chemical stability and achieves an outstanding photocurrent density of 4.42 ± 0.1 mA·cm^-2 at 1.23 V vs reversible hydrogen electrode (RHE), which is 3.7-time higher than that of BVO photoanode. This work supplies an efficient avenue to design photoanode with enhanced photocurrent and stability by using a thin NiFe-MOF layer grafting O_vac-BVO.